Haementeria ghilianii, the giant Amazon leech, is one of the world's largest species of leeches.[1] It can grow to 450 mm (17.7 in) in length and 100 mm (3.9 in) in width. As adults, these leeches are a greyish-brown colour, as opposed to juveniles, which do not have a uniform colour, but rather, a noncontinuous stripe of colour, and patched colouring. They live from the Guianas to the Amazon.[2] The leech produces the anticoagulantproteasehementin from its salivary glands.